GENETIC-ANALYSIS BY PEPTIDE NUCLEIC-ACID AFFINITY MALDI-TOF MASS-SPECTROMETRY

The ability to analyze multiple polymorphic sites rapidly and accurate ly is crucial in all areas of genetic analysis. We have developed an a pproach for the detection of multiple point mutations, using allele-sp ecific, mass-labeled, peptide nucleic acid (PNA) hybridization probes, and direct analysis by matrix-assisted laser desorption/ionization ti me-of-flight mass spectrometry. The composite mass spectra produced co ntain peaks of distinct masses corresponding to each allele present, r esulting in a mass spectral ''fingerprint'' for each DNA sample. The h ybridization characteristics of PNA:DNA duplexes were found to be high ly dependent on both base content and sequence. Results from the analy sis of four polymorphic sites contained in exon 4 of the human tyrosin ase gene show that this approach is simple, rapid, and accurate with p otential applications in many areas of genetic analysis.